Integrally bladed rotors (IBR's), also commonly known as “bladed discs”, are important parts of gas turbine engines. An IBR generally has a disc or hub with an array of blades affixed thereto. The blades extend radially outwardly and are circumferentially spaced apart. The airfoil surfaces of each blade define a complex geometry in order to provide desired aerodynamics. IBR's are used in gas turbine engines, for example as fan rotors which may also be referred to as “IFR's”, compressor rotors or turbine rotors which rotate at high speeds during engine operation either to provide high speed and high pressure gas air flow or to generate power. The accuracy of the complex geometry of the airfoil surfaces of IBR's is important to ensure engine performance. However, it is challenging to achieve the accuracy of the complex geometry of the airfoils of IBR's, due to manufacturing tolerances. For example, when the blades are joined to the hub in a welding process, a reference surface of a blade which is used to define the position of the blade on the hub, can vary up to the addition of positioning tolerance and other manufacturing tolerances of the blade, resulting in deviation of finished surfaces of the blade from the required geometry defined by designed nominal surfaces of the blade. This will affect the performance of the rotors and thus the engine.
Accordingly, there is a need to provide an improved method of fabricating IBR's to minimize IBR geometry variations.